Big Question: The reluctance to strike Islamic State in Syria is
drawing the spotlight on Turkey

As Islamic State (Isil) fighters close their grip on Kobane, a Kurdish-Syrian town on the Turkish border, Turkey’s inaction has been put in the spotlight. Why hasn't Ankara acted against the Isil advance, especially given the military force it has readied just a couple of miles away, and despite approval given by Turkey's parliament to send forces into Syria?

A plague on both their houses ... but especially that of the Kurds

The chief explanation is simple, if hard for some to stomach. Turkey makes no distinction between the Kurdish Workers Party (or PKK), and Isil. The PKK is regarded as a terrorist organisation in Turkey, and the US and the EU also classify it as such.

And Ankara regards the Kurdish Democratic Party (or PYD), which is mounting Kobane’s defence, as an offshoot of the PKK.

In fact, Turkey is hindering Kurdish capacity to defend the town by seeking to prevent Turkey’s Kurds from crossing the border to help their Syrian brethren, and by detaining Syrian Kurds that cross into Turkey.

It has also denied the Kurdish defenders the opportunity to equip themselves so that they can put up a better fight against their more heavily armed opponents.

Unsurprisingly, Kurds on both sides of the border are more convinced than ever that Turkey has long-favoured Syria’s jihadists, and has at minimum turned a blind eye to their smuggling of arms, recruits and supplies from Turkey into Syria, their smuggling of oil into Turkey from Syria, and their resort to Turkish medical treatment for their wounded.

... followed by the house of Assad

Turkey’s chief priority is to overthrow the Assad regime. It would also like to crush the autonomous Syrian Kurdish cantons that have been established by the PYD.

Isil is an effective opponent of both Damascus and the Kurds, and thus useful. Ankara also regards the Syrian Kurdish refusal to join Turkey-sponsored Free Syrian Army (FSA), which refuses to entertain Kurdish demands for autonomy, as evidence of Kurdish sympathies with Assad.

It seems that the defeat of Isil is a low priority for Turkey. Instead, Turkey is holding out for US and allied commitment to the overthrow of the Assad regime, and is unwilling to act alone – not least as Damascus and Tehran would regard any military incursion as an "act of aggression". Only as part of a wider effort might Ankara send forces across the border – and, Kurds suspect, use them to finish off the PYD altogether.

Mr Bill Park is a Senior Lecturer in the Defence Studies Department at King's College London.